Many surface finishing processes, particularly repair processes in the automotive refinish industry, involve the application of fillers to imperfections in the surface followed by progressive abrasion with coarser to finer abrasive materials until the desired smooth surface is achieved. A series of protective coatings is applied, e.g., primer, paint coats, lacquers and so forth, and each layer is normally rubbed down prior to application of the next coat in order to ensure a smooth surface.
In order to assist the operator in identifying areas requiring abrasion and highlighting defects during the repair process, it is known to apply a guide coat to the surface being treated. The guide coats generally comprises a dilute paint mixture which is sprayed over the surface to be treated to provide a light paint coating. As the surface is abraded the guide coat is removed from the higher portions of the surface leaving the visible guide coat on the lower areas. Thus, the surface irregularities are clearly visible to the operator, enabling him to abrade and fill the appropriate areas.
The use of a dilute paint mixture as a guide coat suffers from the disadvantages that it is necessary to mask surrounding areas of surface which are not to be treated and the use of large amounts of volatile solvent is undesirable.
The present invention, described hereinafter, provides an alternative system for use as a guide coat.